Effect Of Magnetic Field On Ni-P Electroless Plating Process Of 316L Stainless Steel Surface After Carburizing

As a widely used austenitic stainless steel,316L stainless steel has attracted much attention.It has many excellent properties,such as excellent corrosion resistance,cold working property and good toughness.But compared with other stainless steel,it has lower hardness(HV200?260)and poor wear resistance.After we improve the hardness and wear resistance of 316L stainless steel by low temperature plasma carburizing,we find that while increasing the surface hardness of the material,the corrosion resistance of the material becomes worse,and at the same time,the surface roughness is increased and the gloss is dim.In order to solve the above-mentioned shortcomings of this process,this paper has conducted targeted research.Taking 316L stainless steel after carburizing as the research object,a Ni-P alloy coating was coated on the substrate of 316 L stainless steel after carburizing by electroless plating.Orthogonal test was used to determine the optimal process procedure for preparing Ni-P alloy coating.The influence of pre-treatment activation,PH value,temperature and time on the wear resistance,adhesion and corrosion resistance of the alloy coating was studied by friction and wear testing machine,coating adhesion scratch instrument and other instruments.The results show that the PH value is 5.1?5.4 when the activated solution is mixed with H₂SO₄-HNO₃-NH₄F,and the electroless nickel-phosphorus plating test under75?is the best.The optimum technological conditions were observed under metallographic microscope.The Vickers hardness value and bonding force of the electroless Ni-P alloy coating reached the maximum values of 518.04HV_100g and 43N,respectively,and the wear resistance and corrosion resistance were also significantly improved.Innovatively,the magnetic field technology is introduced on the basis of optimizing the preparation of Ni-P alloy coatings,and the bonding strength and corrosion resistance of Ni-P alloy coatings are further improved,and coatings that meet the requirements of use are obtained.By applying a constant static magnetic field and an alternating magnetic field,a comparative test is conducted under conditions such as magnetic field strength and magnetic field change mode,and a horizontal control group is formed between the Ni-P alloy coating obtained under the magnetic field and the Ni-P alloy coating not applied with a magnetic field To compare the process and performance tests,the results show that:(1)Both the applied static magnetic field and the alternating magnetic field have an effect on the bonding strength and other properties of the Ni-P alloy coating.(2)Electroless plating is carried out under the application of a constant static magnetic field.Through analysis of the performance characteristics of the plating layer,it is found that the bonding force,hardness value,friction coefficient,etc.of the plating layer tend to increase first and then decrease as the strength of the magnetic field increases.The coating has the best overall performance when the constant static magnetic field strength is 14.83m T.(3)Electroless plating under an alternating magnetic field has a significant effect on the bonding force and friction coefficient of the coating.The bonding force,hardness value and friction coefficient between the coating and the base material,the corrosion resistance performance gap is small,and the comprehensive performance is optimal at 20V.